TweakGames

iTrader: (3)

Hello. I just got my street ported RE, t04s tuned, and I am more than happy with the tune (BDC FTW), but a little unhappy with how the turbo is responding.

I will post up a log later tonight, but I don't get 10 psi till about 5,000 rpm (4th gear), and I have a t04s .84 divided (with divided manifold) and a 3 inch crush bent exhaust. I am thinking about upgrading to a 3 or 3.5 inch mandrel bent exhaust.

My question is: is there some sort of equation or estimation on how much crush bent exhausts hurt the general "size" of the tube? An example I mean would be a 45* crush bend would normally have to crush the pipe 20%, making a 3 inch tube turn into a 2.4 inch?
Wow I hope it's less than 20% cause 2.4 inches sounds REALLY small for our engines.

Any opinions on the matter?

Thanks
~Tweak

CrackHeadMel

iTrader: (2)

You have some issue somewhere for sure, my unported RE with a to4s with a 1.0 hotside had 10lbs well before that

id deffinetly ditch the crush bent downpipe, however whats the rest of the exhaust system consist of? what about the intake? can you post photo's of the engine bay and exhaust, maby something will stick out to someone.

TweakGames

iTrader: (3)

Yes definitely. I will post a more recent picture and log tonight, but here is the gist of it.







I don't have a cat or anything else except the apexi n1 muffler and a 4 inch "cherry bomb" in the middle. I didn't choose it, it was already on this exhaust.

Is there any more specific pictures you would like when I Take some tonight?

Yeah I thought it was kinda laggy, but WOW it takes off when it does reach 5k. I just wish it was a little more linear and smooth up to that point.

Here is a log I pulled off my laptop from the last time I boosted.


4944 rpm to finally reach 10.5 psi. O.o

classicauto

iTrader: (3)

Where's your EGT probe(s) and whats the temps in those locations?

Also, what type of front mount/size etc?

Was the turbo used? how's the turbine wheel look? does it spin freely?

EDIT: I'd also check for boost leaks. Could be a slight leak at the TB o-ring or something like that.......

TweakGames

iTrader: (3)

Hi classicauto!

The turbo is brand new. Has 3000 non boosted miles on it. (I didnt boost till I got tuned). I will check to see if it still spins freely. The dual digital EGT probes are mounted in the turbo manifold 4 ta 5 inches from the engine. I will have to check out their temps tonight.

The front mount is a generic one, not too big, a little larger than our oil coolers. It said "JDM" on the bottom. I tested for boost leaks by pressurising the system and spraying soap over everything, I didn't see any leaks.

C. Ludwig

iTrader: (27)

What is PWM 4 controlling? Are you just running on the wastegate spring? What kind of manifold? What kind of wastegate?

TweakGames

iTrader: (3)

Hi C. Ludwig.

Yes I am running a wastegate spring. It is a 7 lb spring, but my wastegate is getting it's source RIGHT after the turbo instead of off the same source after the TB like my pressure sensor so when I run wastegate spring only I hold 5 psi all day.

I have a real tial 38mm wastegate.

It is a generic divided t4 turbo manifold that has both runners feeding the wastegate.

PWM 4 is the haltech boost controller. I have been playing with it for over 9 hours now attempting to get it to work properly. Sometimes it holes boost, sometimes it doesn't. But when it does, this is one of the logs I get.

I am getting more sucessful with it working correctly, I think the main things I need to play with now are the PID's.

CrackHeadMel

iTrader: (2)

is the wastegate opening prematurly?

TweakGames

iTrader: (3)

..... I was thinking that...... tonight I am going to do some more tests. Disable the pwm4 (boost solenoid) from opening till 10 psi. I will have to do some extra testing so that it will catch it, but I think it can be done. Right now ... looking at that specific log, it looks like it might be acuating the solenoid and slowly letting it get up to boost.... if so ... I really dont like the way the solenoid needs to be programmed so much. I wish I would have got a profec b.

TweakGames

iTrader: (3)

I just did some research on how PID's work. Pretty interesting to say the least... it also gave me some ideas on how to get things set (steps and such). I feel as though I am going to get this thing figured out tonight.

13B-RX3

iTrader: (2)

Good luck. Let us know when you unlock the secrets.

C. Ludwig

iTrader: (27)

I would stick a manual controller on there and see how it acts. If it comes on boost more quickly you know what the variable is.

Secondly, you can see in your datalog that the wastegate solenoid is active well before you reach your boost target. You might try setting it up on duty cycle only (turn the closed loop function off) so that you get a better idea of what duty cycle you need where to get good boost rise without overshooting the target. Once you know what you're looking for as far as DC v RPM you'll know what you need to get out of the closed loop mode.

JEROME

Here is some very usefull information on what tubo exhaust. No I can't give you the secret formula b/c your not a fluid dynamic engineer. you may want to check my post on 4" exhaust. My turbine housing uses a cone that is incorporated in the flange. You are choking the turbine.


Here is a close up of the tapered cone looking down the bore into the throat of the turbot's exhaust port. Note how the pipe is properly sized and properly centered to maintain high velocity turbulent-free exhaust flow out of the turbo for the purpose of heat extraction and maximum flow enhancement.



Turbine Exhaust Gas Theory.


Where the tapered cone section begins the exhaust stream will be allowed to expand. Allowing the exhaust stream to expand also causes the exhaust velocity to drop and the exhaust gas temperature to drop. Additionally, a significant heat load is transferred to the exhaust pipe itself. If the pipe dimensions are setup up correctly, an "expansion chamber" effect can be realized much like how two-stroke motorcycle exhaust systems are designed to operate. The benefit from this is a "scavenging effect" where the exhaust is "sucked out" of the turbo or at least backpressure is reduced to a negligible amount. It is the goal to exploit this simple and "free" exhaust extraction technique by deliberate designing it in from the beginning rather than later like all those who follow will do if the execution of this theory proves successful.


This is also a great link.
http://en.wikipedia.org/wiki/Turbocharger

TweakGames

iTrader: (3)

AWESOME! It is like you read my mind! I was thinking this morning, how the heck am I going to get my 3 inch out on my turbo to mate up with a 3.5 or 4 inch downpipe?!? There is the answer. Also you solved my problem wondering if I should have slowly tapering setup, or something that instantly goes to 4 inches. I guess I will have to do some more research.

THANK you.

Now off I go to play with my PIDs some more.

rxspeed7

iTrader: (5)

you may also want to rethink your charge pipe config. theres a lot o tight bends and rubber hose.

classicauto

iTrader: (3)

Off your turbo, you could build a 4" system starting with one of these:

http://www.atpturbo.com/Merchant2/me..._Code=ATP-FLS2

SIDEWAYZE_FC

iTrader: (1)

I ran .84 hotside with .70 cold on my setup, even have a crushed bent downpipe like yours, and id have 10lbs right after 3kRPM. Maybe your wastegate? I have a 50mm hks on my setup. maybe thats the difference.

hope ya figure out soon, gonna snow round spokane area here pretty quick.

classicauto

iTrader: (3)

Also just thought....how's the wastegate connected to the manifold? Any possible leaks there? any possible leaks at the tubine housing to manifold flange? engine to manifold flange?

TweakGames

iTrader: (3)

I don't think so, but next weekend, I am going to have to take everything off and see if I have some warped flanges or what. If I am supposed to have 10 psi by a little over 3k, than I DEFINILTY have something wrong with my setup, cause I don't even have 5 (wg spring) psi by then. :/ That kinda eliminates the hole solenoid acting up thing.

Also, at the time, when I first got my tial wastegate, I could see a little gap between the valve and where it seats. I thought that was weird and that it was supposed to seal perfectly, so I put some water there to see if it would drip by, and it did. Could that be my problem or is a little leak by the WG normal?

classicauto

iTrader: (3)

That could be your problem It shouldn't leak. If it will allow some water to go past it in an ideal condition - it'll probably allow some pressure by it when there's 5psi in the manifold.

TweakGames

iTrader: (3)

Yeup, I talked with tial over emails. (BTW AMAZING SERVICE! Definitely worth the extra $) He wants me to take the WG off and take some pictures. I am going to be doing that tonight. He thinks that possibly I have a bad valve seat. But then again, I hope so, so I can have an easy fix.

blimp

iTrader: (2)

i wonder what the problem is? Hopefully you find out soon.

Ya i have a t04s with a .96 hotside and my spools a whole lot quicker than that. I also have a street port and a vmount so who knows.

classicauto

iTrader: (3)

Also, if you have a dump tube or the wastegate isn't recirculated, idle the car and get under it and feel around the tube - there shouldn't be *any* exhaust puffing out. If there is - that's the problem.

TweakGames

iTrader: (3)

Yeah, I think I made a mistake and recirculated it. :/ I think I will have to change that with the next exhaust I put on. I am excited to get working on the car in 3 hours. I will take pictures.

Thanks for all the support guys. It's scary to imagine my car getting full boost so early (3.5 - 4k) I can barely handle it now. O.o

TweakGames

iTrader: (3)

Well I just took the WG off in the dark (I would rather jump into a pool naked that was filled with hungry penguins btw), and I looked at the valve again. I noticed that the "valve seat" was flush with the wastegate now, and that there was no light slipping past the valve any more. I think it did before because the valve seat wasn't forced against the valve.

In about an hour I'm going to head out again just to see if maybe the re-tightening of the bolts helped something seal.

After that I if I still have 10 psi later than 4.5k rpm I'm going to lift the car again and look for exhaust leaks in the turbo manifold. :/